Field of the Disclosure
Aspects of the present disclosure generally relate to beamforming in air-to-ground wireless applications (e.g., where a base station provides service to one or more airborne devices) by performing beamforming on one or more subbeams prior to transmission and using one or more beamformed subbeams to communicate with connected UEs (e.g., aircraft).
Description of Related Art
Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, Long Term Evolution Advanced (LTE-A) systems, and Orthogonal Frequency Division Multiple Access (OFDMA) systems.
Generally, a wireless multiple-access communication system can simultaneously support communication for multiple wireless terminals. Each terminal communicates with one or more base stations via transmissions on the forward and reverse links. The forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations. This communication link may be established via a single-input single-output, multiple-input single-output or a multiple-input multiple-output (MIMO) system.
In Air-to-Ground (ATG) systems used to provide Internet access to airplanes, the airplanes are generally considered wireless terminals (or user equipments) and communicate with terrestrial Ground Base Stations (GBSs) as the airplanes fly over land. A currently used ATG system operating over the continental United States uses 4 MHz of spectrum in the 800 MHz band. While this system may become commercially viable, the limited spectrum may be inadequate to accommodate increasing demand for Internet services, such as streaming of Internet content to aircraft or other bandwidth-intensive operations.
Accordingly, improvements in ATG systems that would accommodate the increasing demand for Internet services are desirable.